Can you hear that sound, adventurer? It’s the sound of the rushing rivers and perilous peaks of Skyrim calling to you. Did you think your quest was at an end just because you saved the world? There is still more to do. Bethesda has just released the Dawnguard expansion on the PC through Steam, so get your questing pants on, folks.

This is a completely new quest with new missions and a mysterious guild known as the Dawnguard. In this new story, the Vampire Lord Harkon has returned from the dead (as vampires tend to do), and he plans to use the Elder Scrolls to destroy the sun, plunging the world into a perpetual night ruled by the undead. It’s your job to stop him… unless you don’t want to.

Dawnguard lets you make the choice between joining the Dawnguard and fighting the vampire menace, and becoming a vampire lord yourself. Each path comes with its own spells, items, armor, perks, and shouts — all of which are new to Dawnguard. There are plenty of new locations and creatures in the land of Skyrim to keep you occupied, as well. You can also finally do something with all those dragon bones. Specifically, they can be forged into weapons.

Dawnguard is a completely new quest that requires you already have Skyrim installed. Dawnguard will run you $20 on Steam, and the developer is good enough to offer the original full version of Skyrim at 50% off at the moment. That means you can get Skyrim and Dawnguard for just $50. That’s less than Skyrim cost at launch. That $50 gets you many dozens of hours of gameplay, too. This download is only 1.1GB, so you should be able to fit in plenty of play time if you pick it up now.